Load test charts with standard deviation and percentile statistics

1. A computer-implemented method for real-time analysis of results obtained from a load test as the load test is being performed on a target website, comprising:

(a) computing first-level aggregated test results within each of a plurality of load server instances that generate a load on the target website, the first-level aggregated test results including first-level statistics computed from a set of data points received over a time period by each of the load server instances from the target website, the first-level statistics being computed by an embedded component coupled with a memory within each of the load server instances, the first-level statistics including a sum of the data points, a count of the number of the data points, a sum of squares of the data points, and an average of the data points;

(b) sending the first-level aggregated test results over a network from each of the load server instances to an associated one of a plurality of analytic server instances;

(c) aggregating, in one or more analytic server instances, all of the first-level aggregated test results computed by the load server instances resulting in second-level aggregated test results;

(d) aggregating in a main instance computer, which includes a processor coupled with a memory, all of the second-level aggregated test results resulting in a cumulative sum, a total count, a total sum of squares, and a cumulative average, of all of the data points across an entire data set;

(e) calculating by the main instance computer a standard deviation result (STDEV) as

STDEV=SQRT[{( X 1 2 +X 2 2 + . . . +X N 2 )+ NA 2 −2 A ( X 1 +X 2 + . . . +X N )}/ N];

where N is the total count, A is the cumulative average, X 1 , X 2 . . . X N are the data points across the entire data set, (X 1 2 +X 2 2 + . . . +X N 2 ) is the total sum of squares, and (X 1 +X 2 + . . . +X N ) is the cumulative sum; and

wherein steps (a)-(e) are each performed in real-time as the load test is being performed on the target website.

2. The computer-implemented method of claim 1 further comprising:

(f) providing on the main instance computer a graphical user interface (GUI) that displays a chart on a screen, the chart providing a visual representation of a performance metric for the load test based on the standard deviation result.

3. The computer-implemented method of claim 2 further comprising:

communicating the standard deviation result to a browser application running on the main instance computer, the browser application providing an analytic dashboard with the graphical user interface.

4. The computer-implemented method of claim 2 wherein the chart is generated in real-time responsive to an input command of the graphical user interface.

5. The computer-implemented method of claim 1 wherein the performance metric comprises a confidence interval percentile (X).

6. The computer-implemented method of claim 1 further comprising calculating by the main instance computer the confidence interval percentile (X) as

X ={( A +( Z *STDEV)};

where Z is a constant used for calculating a certain percentile.

7. The computer-implemented method of claim 1 further comprising calculating by the main instance computer a delta STDEV based on incremental changes occurring as the load test is running in real-time.